1. Field of the Invention
The present invention generally relates to a steering column apparatus, and more particularly to a steering column apparatus, which has a telescopic mechanism, for a vehicle and to a steering apparatus, which has both a telescopic mechanism and a tilting mechanism, for a vehicle.
2. Background Art
The telescopic mechanism and the tilting mechanism are mechanisms for adjusting the height of a steering wheel and an angle of inclination to a position, in which a driver can drive the vehicle, according to the figure and the taste of the driver.
The telescopic mechanism and the tilting mechanism are each provided with a clamp/unclamp mechanism to be operated when the height of the steering wheel and the angle of inclination are adjusted. At this adjustment, the clamp/unclamp mechanisms therefor are once unclamped. After the height and the angle of inclination are adjusted in that state, the clamp/unclamp mechanisms are brought into a clamped state again.
The adjustment of the height of the steering wheel and the angle of inclination is performed by manually operating the steering wheel. Thus, it is preferable that the clamp/unclamp mechanism can be operated without unhanding the steering wheel. The specification of British patent application publication No. 2281375 discloses a steering column apparatus provided with a single operating lever that can be operated while the hands of a driver are kept put on the steering wheel.
In the steering column disclosed in the aforementioned British patent application publication, the clamp/unclamp mechanism of the telescopic mechanism is provided at a side thereof, which is fixed to a vehicle body. An operation lever, the tilting mechanism, and the clamp/unclamp mechanisms thereof are provided at a steering wheel side, the height of which is adjusted with respect to the vehicle body. Therefore, the operation lever is disposed apart from the clamp/unclamp mechanism of the telescopic mechanism. Additionally, the distance therebetween varies as the height of the steering wheel is adjusted.
Thus, the movement of the operation lever is transmitted to the clamp/unclamp mechanism of the telescopic mechanism through a cable enabled to move in a flexible tube. Large flextures are imparted to this cable and the tube so as to provide a sufficiently small curvature enabling the cable to freely move in the whole adjustment range of the steering wheel. Thus, the cable and the tube partly protrude outwardly from the steering column apparatus. This is not only indecorous but causes troubles. Further, the transmission mechanism consisting of the cable and the tube is poor in reliability. Additionally, the cable expands and contracts, so that the operability of the apparatus is not favorable.